If you have allowed the group to overheat following a low water level incident these can warp and become brittle. Over time this will affect the performance of the piston and reduce the quality of the shots. Included (Part numbers from the diagram). 1 x Stainless Steel Jacket for Coffee Group no.
1 x Gasket for Jacket for Coffee Group no. Please note these are only found in the grouphead of the post millennium models (right in the 5th photo). Thanks for taking the time to have a look at the item.